Combination tail pipe and muffler



Nov. 13, 1956 s. e. JOHNSON COMBINATION TAIL PIPE AND MUFFLER FIG.3

INVENTOR SAMLEL s. JOHNSON Filed Jan. 19, 1952 ATTY United States Patent"ice COMBINATION TAIL PIPE AND MUFFLER Samuel G. Johnson, Fort Wayne,Ind., assignor to Intergational Harvester Company, a corporation of Newersey Application January 19, 1952, Serial No. 267,248

7 Claims. (Cl. 181-41) This invention relates to a combined muffler andtail pipe for internal combustion engines or the like, and moreparticularly to a simple and inexpensive device for reducing the exhaustgas noise without materially increasing the back-pressure of the engine.

Present day automobile engine noise silencing systems generally includea pipe which has one end connected to the exhaust manifold of theengine. The pipe is curved downwardly and is attached to a mufflerhaving a camparatively large diameter and length. A tail pipe is usuallyattached to the muffler to conduct the exhaust gases to the atmosphere.The muffler and tail pipe are disposed below and supported by thechassis frame and because of the construction of the chassis frame whichincludes cross-frame members longitudinally spaced along the chassisframe and the other vehicle parts such as the drive shaft and rear axlelocated below the chassis frame, it is oftentimes difficult to positionthe muflier beneath the chassis frame. In other Words, a particularmufiier possessing the sound-deadening characteristics needed forefficiently operating a given engine could not be utilized because ofthe lack of space to mount the same beneath the chassis frame. It is,therefore, the primary objective of the present invention to provide aunitary structure leading from the engine to the atmosphere which can beshaped to conform to the underside of the chassis frame and which willefiiciently mufiie or deaden the engine exhaust explosions with aminimum of back-pressure without the need of a bulky, cumbersomeseparate muffler in addition to the tail pipe.

A further object is to provide combined muffler and tail pipe structurecomprising a single pipe which may be of any desired length andpreformed in irregular shapes to conform to the contour of the undersideof the vehicle without impairing the noise silencing efliciency of thestructure.

A still further object is the provision of an inexpensive combinedmuflier and tail pipe structure which includes :a single corrugated tubeenclosed by a single pipe which are easily assembled together.

The foregoing and other important objects and desirable featuresinherent in and encompassed by the invention together with many of thepurposes and uses thereof will become readily apparent from a reading ofthe ensuing description in conjunction with the annexed drawings, inwhich:

Figure l is a side elevational view of a motor truck chassis frameequipped with a new and improved combined muffler and tail pipe;

Figure 2 is a plane view of the combined muffler and tail pipe detachedfrom the chassis frame;

Figure 3 is an enlarged detail view, in section, taken substantiallyalong line 3-3 of Figure 2;

Figure 4 is a fragmentary sectional view taken substantially along line4-4 of Fig. 2; and

Figure 5 is a view similar to Figure 2 showing a modification of theinvention.

' the atmosphere.

Patented Nov. 13, 1956 Referring to the drawings, wherein like referencecharacters designate like elements throughout the various views, thereis shown a motor truck chassis frame 10 comprising a pair of laterallyspaced side sill members 11 (one of which is shown) interconnected by aplurality of longitudinally spaced cross members 12. An internalcombustion engine 13 is secured to the forward end of tthe chassis frame10 and is provided with an exhaust manifold 14 on one side thereof.

The combined muflier and tail pipe structure, designated generally bynumeral 15, extends rearwardly from the exhaust manifold 14 to rear ofthe chassis frame 10 or other appropriate point where the exhaust gasesare expelled to the atmosphere. The combined mufiler and tail pipestructure 15 is supported by brackets 16 or other suitable meansattached to the side sill members The combined muffler and tail pipestructure 15 includes a steel pipe 17 which serves as the outer casingfor the structure 15. One end of the pipe 17 is flared outwardly, asbest shown in Figure 4, to provide a flange 18. A collar 19 whichencircles the pipe 17 has an annular surface 20 for engaging the flange1S and a plurality of spaced apertures 21. Bolts 22 are shown extendingthrough the apertures 21 into aligned threaded recesses formed in theexhaust manifold 14 to tightly clamp one end of the pipe 17 to themanifold.

Inserted within the pipe 17 and having substantially the same length asthe pipe is a flexible corrugated tube 23. The ends of the tube 23 arewelded to corresponding ends of the pipe 17. As best shown in Figures 3and 4, the rounded crest portion 24 of each corrugation 25 abuts theinterior surface 26 of the pipe 17. It will also be noted that thecorrugations 25 are spaced along the entire length of the pipe 17 andlie in planes normal to the axis of the pipe 17 to form a series ofsuccessive ring-like expansion pockets or chambers 27, each chamber 27being defined by the crest portions 24 of adjacent corrugations 25, thevalley portion 23 joining the successive crest portions and the interiorsurface 26 of the pipe 17. A plurality of apertures 29 are formed in thevalley portion 23 of each corrugation 25 to provide passages for theflow of the exhaust gases to and from each expansion chamber 27.

In operation, the hot exhaust gases which are emitted by the engine 13under pressure enter the tube 23 at one end thereof and flowcomparatively freely therethrough to the opposite end where they aredischarged to It will be obvious that by constructing the mufiier andtail pipe in this manner the back pressure is practically negligiblesince there are substantially no obstacles in the path of the exhaustgases to impede the flow of the same. While the exhaust gases areflowing through the tube 23 a percentage of the flow is allowed to enterthe expansion chambers 27 where the pressure of the gases is decreasedsuddenly to deaden the explosion noises. inasmuch as each chamber 27 isseparated from the atmosphere by a thin metallic wall section (pipe 17)the exhaust gases which enter the chambers 27 are rapidly cooled tofurther decrease the pressure of the gases and to lessen the possibilityof explosions of the gases in the mufller and tail pipe structure 15 bylowering the temperature of the same. From the foregoing it will beappreciated that the velocity of the exhaust gases flowing through thestructure 15 is decreased by continually lowering the pressure of thegases as the flow from one end of the structure to the other toconsequently decrease the objectionable exhaust noise of the engine 13.

It will also be clear from the foregoing that the combined muffler andtail pipe structure 15 is not only eflicient in operation but simple andinexpensive to manufacture. In order to construct the structure 15 it isonly necessary to insert a length of flexible corrugated tubing havingapertures drilled into the valley portion of each corrugation in astraight piece of steel pipe having a predetermined length. '1" he endsof the tube are then welded to respective ends of the pipe and theentire assembly is bent or formed in any desired configuration. Inasmuchas the tube is flexible there is no danger that the forming operationwill cause the tube to buckle or break. Furthermore, the various bendsand curves formed in the pipe tend to maintain the tube snugly andsecurely within the pipe. The fact that the structure may be formed inany desired configuration without impairing the operating efficiency ofthe same is deemed extremely advanta geous. Heretofore in certaininstallations employing a conventional mufiler and tail pipe theefliciency of the exhaust system had to be sacrificed to accommodate theequipment in the vehicle because of space limitations. The combinedmuffler and tail pipe structure 15, once it has been formed and adaptedfor a particular vehicle, is rigid and will remain rigid and free fromrattles or other obnoxious noises during the period of use of thestructure and for all practical purposes is a single, unitary structure.

In certain installations it is not necessary to employ a flexiblecorrugated tube which extends fully from one end of the pipe to theother end. As shown in Figure 5, a corrugated tube 30 of the sameconstruction as tube 23, but having a length less than the outer sheathor pipe 17, has one end secured to a pipe 31 adjacent an attachingcollar 32. The pipe 31 and pipe 17 are substantial duplicates infunction and construction.

The embodiment of the invention chosen for the purposes of illustrationand description herein is that preferred as the result of selectivetests based upon the requirements for achieving the objects of theinvention and developing the utility thereof in the most desirablemanner, due regard being had to existing factors of economy, simplicityof design and construction, production methods and the improvementssought to be effected. It will be appreciated, therefore, that theparticular structural and functional aspects emphasized herein are notintended to exclude, but rather to suggest, such other adaptations andmodifications of the invention as fall within the spirit and scope ofthe invention as defined in the appended claims.

What is claimed is:

l. A combined mufiier and tail pipe assembly for internal combustionengines comprising a single gas-impervious pipe extending from theexhaust manifold of the engine to the area where the exhaust gases areexpelled to the atmosphere; a single flexible corrugated tube havingsubstantially the same length as said pipe disposed within and immovablewith respect to said pipe, the crest portionof each of the corrugationstightly abutting the interior surface of said pipe to provide aplurality of spaced ring-like pockets, said pockets each being definedby crest portions of successive corrugations, the interior surface ofsaid pipe, and the respective valley portion joining successivecorrugations, said valley portions being provided with a plurality ofspaced apertures for establishing gas communication between said tubeand said pockets.

2. A combined muffler and tail pipe assembly for internal combustionengines comprising a single gas-impervious pipe extending from theexhaust manifold of the engine to the area where the exhaust gases areexpelled to the atmosphere; a single conduit having substantially thesame length as said pipe for conducting the exhaust gases from theengine to the atmosphere, said conduit being disposed within andimmovable with respect to said pipe, said conduit being formed topartially define a plurality of gas expansion chambers spaced along thelength of said pipe, said chambers being interposed between the interiorsurface of said pipe nad the outer surface of said conduit, each of saidexpansion chambers being in gas communication with the interior of saidconduit.

3. A combined muffler and tail pipe assembly for internal combustionengines comprising a single rigid, gasimpervious pipe of uniformdiameter throughout its length extending from the exhaust manifold ofthe engine to the area where the exhaust gases are expelled to theatmosphere; a single flexible conduit disposed within and .immovablewith respect to said pipe for conducting the exhaust gases from theengine to the atmosphere, said conduit being formed to partially definea plurality of means spaced between said conduit and said pipe forallowing the exhaust gases to expand, said means being disposed alongthe entire length of said conduit and each means being spaced from anadjacent means a distance less than the diameter of said pipe.

4. The combination as set forth in claim 3, in which said means includesa plurality of ring-like expansion chambers.

5. A combined mufiler and tail pipe assembly for directing exhaust gasesfrom an engine to the atmosphere including a rigid, deformable,elongated pipe; said pipe being capable of retaining its deformed shape;a flexible conduit disposed within and immovable with respect to saidpipe; said conduit being formed to partially define a plurality of meansspaced between said conduit and said pipe for allowing said gases toexpand, each of said means being spaced from an adjacent means along thelength of said pipe a distance less than the diameter of said pipe.

6. The combination as set forth in claim 5, in which said means includesan expansion chamber interposed between said pipe and conduit.

7. A combined mufller and tail pipe assembly for internal combustionengines comprising a pipe of uniform diameter throughout its lengthextending from the exhaust manifold for directing exhaust gases to theatmosphere, said pipe being gas-impervious; and structure disposedwithin said pipe and formed to partially define a plurality of expansionchambers disposed within said pipe and spaced along the length of saidpipe, said expansion chambers being fixed with respect to said pipe,each of said expansion chambers being in gas communication with theinterior of said pipe and being spaced from an adjacent expansionchamber a distance less than the diameter of said pipe.

References Cited in the file of this patent UNITED STATES PATENTS1,302,300 Brinkman Apr. 29, 1919 1,611,475 Maxim Dec. 21, 1926 1,947,987Hathorn Feb. 20, 1934 2,565,184 Parlasca Aug. 21, 1951 2,583,956 Lindsayet al Jan. 29, 1952 FOREIGN PATENTS 704,741 France May 26, 1931 435,423Great Britain Sept. 20, 1935 650,784 Germany Oct. 1, 1937

